You can use Unicode symbols in GHC Haskell for e.g. λ. Then there's APL of course which also re-uses a lot of ancient Greek and other symbols that these days would most likely be in Unicode.

https://wiki.haskell.org/Unicode-symbols

https://en.wikipedia.org/wiki/APL_(programming_language)

https://www.youtube.com/watch?v=a9xAKttWgP4